Delusional misidentification syndromes: A review of the anglophone literature

Delusional misidentification syndromes (DMS) include a number of discrete but related syndromes which have in common the concept of the double. In this review article, the classification, epidemiology, aetiology, and pathogenesis of these syndromes are examined in detail. DMS are relatively rare and occur predominantly in association with schizophrenia and affective psychosis. Between 25-40% are associated with organic conditions such as dementia, head injuries, brain tumours and epilepsy. There is now growing evidence that patients with DMS have impaired face recognition memory in the absence of any impairment of verbal recognition memory. Frontal and temporal lobe abnormalities have been shown to be associated with DMS. It is likely that the study of these syndromes will lead to a greater understanding of the neurological basis of psychotic experiences and may provide a paradigm for how the psychoses should be investigated.